Thermoforming is a manufacturing process where a plastic sheet is heated to an elevated temperature and is formed to a specific shape defined by a mold, and then is generally trimmed to create a product. The plastic sheet is heated to a high-enough temperature such that the sheet can be stretched into or onto a mold and then cooled to form a shaped product.
In some applications, an image, such as a two-dimensional (2D) printed image, is printed on a thermoforming material, such as a plastic sheet, which may then be thermoformed or vacuum-formed to produce a three-dimensional (3D) surface. The 2D image may be printed on the thermoforming material, such as the plastic sheet, by using vacuum formable inks. However, during the thermoforming process the 2D printed image may be distorted depending upon the complexity of the 3D shape (e.g., the geometry or surface curvature). Common methods for creating 3D surfaces using thermoforming processes or vacuum forming process may require a trial and error process to make adjustments to the 2D image to account for changes during the 3D forming process.
Various engineering software programs have been developed to estimate the vacuum forming distortion effects on vacuum formable inks. Estimations or predictions of the deformed positions based upon theoretical modeling may depend upon the deformed materials and their properties, and may also depend upon the various ways in which the 3D surface may deform locally. In absence of an accurate physical model of the material properties and the deformation effects, it is typically extremely difficult to accurately estimate or predict the texture coordinates needed to account for the deformation process.
There have been techniques developed for forming reproducible 3D vacuum-formed surfaces or objects. For example, U.S. Patent Publication 2009/0180712 to Mark Pollack et al. discloses a grid technique, which uses printed grid lines of colored quads to measure and compensate distortions at specific grid intersections or grid points. However, the grid technique does not produce accurate 2D prints or images input material for complicated geometries or shapes, such as those including fine details. Also, when analyzed automatically, such as by a computer, the grid technique typically will not produce accurate print images for concave shaped geometries because after forming the grid lines will not be continuous over a 3D geometry with a concave region. In particular, the grid lines may “disappear” as viewed by the computer near the concave region, reducing the ability to use those lines to determine the distortion effect after forming. In other words, the grid line technique produces occlusions so that certain features will not be detectable using an automated process. Further, increasing the density of the grid does not correlate with a higher sensitivity for the technique as the probability of errors may increase as the number of grid lines effected by concave regions may become higher.
It is with these shortcomings in mind that the present disclosure has been developed.